I understand what you write and indeed it is my experience that many literary estates act like that - but in case of the Tolkien Estate I don't know one author who actually had to "pay" the Estate to publish about Tolkien.Do you think SO MANY books would have been published about the professor if all they were after was money? I believe it is mainly about trust, the good name of Tolkien and now already 4 generations that depend on it...

You also have to see that the copyright is there "possession" - and so if you want to do anything you will need to ask permission. Why is it logic so for people to ask permission to lend items, to enter archives, etc but think they can publish anything they like. It is not because I own many handwritten letters by J.R.R. Tolkien that I can just start publishing them... don't you see the logic?

Anyways, if you wish I can talk about some other literary estates and tell how they work and how they truly 'monetize' the copyright and then you will feel that the Tolkien Estate is very easy. All depends of course on how (and when) you approach them...